1. Field of the Invention
The present invention relates to a beverage extraction device which can be provided in the main body portion of a vending machine or the like.
2. Description of Related Art
In this type of the beverage extraction device, powder material such as coffee is mixed with hot water and decocted. Then, the decoction liquid is passed through a filter, and extracted. The specific structure is disclosed in Published Unexamined Japanese Patent Application No. 61-31110 and Published Unexamined Japanese Patent Application No. 61-31108. Published Unexamined Japanese Patent Application No. 61-31110 discloses a structure in which an extraction chamber is provided on the upper surface of an extraction receiver so as to sandwich a filter, and powdered material of coffee and hot water are supplied to the extraction chamber. In this state, high pressure air is supplied through the filter from the under side of the filter into the extraction chamber, so that the powdered material and hot water are mixed in the extraction chamber by the high pressure air and thus decoction liquid is generated. Thereafter a piston is moved down to the lower portion of the extraction chamber from the upper portion thereof so as to extract decoction liquid, so that decoction liquid is passed by pressure through the filter and is extracted at the under side of the filter.
Moreover, Published Unexamined Japanese Patent Application No. 61-31108 discloses a structure in which a material inlet is formed in the upper portion of an extraction chamber, and a valve mechanism for opening and closing the material inlet is provided. Powdered material and hot water are supplied into the extraction chamber through the material inlet and high pressure air is supplied through a filter from the underside of the filter into the extraction chamber, so that the powdered material and hot water are mixed in the extraction chamber by the high pressure air and a decoction liquid is generated. Thereafter the material inlet is closed by the valve mechanism, so that the inside of the extraction chamber is airtight, and high pressure air is sent into the upper portion of the extraction chamber, so that decoction liquid is pressurized by the high pressure air and decoction liquid passes through the filter by the air pressure, and is extracted to the lower portion beneath the filter.